The present disclosure relates to forms for pouring concrete columns, and particularly relates to concrete forms for pouring non-round columns, such as rectangular or square columns.
A wide variety of concrete forms for pouring columns have been developed over the years. Forms constructed from lumber and plywood have been used in the past, but are relatively complicated and require substantial skill on the part of the worker to construct. Additionally, wooden forms are relatively expensive.
More recently, it has become conventional to pour concrete columns using a form comprising a wound paperboard tube lined with some type of impervious liner. These forms are less costly than wooden forms and have proven to be very successful, but are limited to the formation of round columns. Various modifications of this basic type of form for making non-round columns have been proposed. Most of these modifications entail forming an insert that defines an inner channel having the desired non-round cross-section. The insert often is formed in part by polymer foam such as polyurethane foam or expanded polystyrene. The insert is positioned within an outer tube such as a wound paperboard tube. Concrete is poured into the inner channel of the insert. Once the concrete cures, the outer tube is removed and then the insert is stripped off the concrete column.
Some of these forms for non-round columns have inserts that are not amenable to being assembled in the field and thus must be pre-assembled in the factory and then shipped to the jobsite. The forms shipped in this manner are bulky and therefore shipping costs are relatively high. Additionally, some of these forms are not amenable to being stripped from the concrete column in a manner allowing the insert to be reused one or more additional times. In the case of forms that employ polymer foam, in many instances the foam becomes exposed and torn or disintegrated as the insert is stripped from the column. Tiny foam pieces then are blown about the jobsite by the wind.
It would be desirable to provide a form for non-round columns that is readily assembled in the field, has at least partial reusability, is amenable to nesting of multiple forms to reduce volume and hence shipping costs, and is relatively simple and inexpensive to produce.